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111.
An efficient synthetic strategy has been developed for the synthesis of a pentasaccharide repeating unit of the O-antigen of Escherichia coli O102 strain. The target pentasaccharide 1 has been synthesized using a [2+3] block glycosylation strategy. All glycosylation steps are highly stereoselective and high yielding. Concept of armed-disarmed and orthogonal glycosylation strategies has been applied during the synthesis. The target compound has been synthesized using the minimum number of steps. 相似文献
112.
Rajesh Chakraborty Sanjoy Dhara Sukalyan Basu Pabitra Chattopadhyay 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):55-59
An inorganic ion exchanger, quinolinephosphomolybdate has been synthesized and characterized by elemental analysis, infrared
(IR) and X-ray diffraction (XRD) spectroscopy. This compound is highly stable toward thermal, chemical and radiation dose.
This has been employed in the separation of carrier-free 90Y from its parent 90Sr from an equilibrium mixture. The absorbed daughter was recovered by using 0.0284 mol L−1 ascorbic acid solutions at pH 5.0 as eluting agent. 相似文献
113.
Ananthaiah J Rajeswari M Sastry VS Dabrowski R Dhara S 《The European physical journal. E, Soft matter》2011,34(8):74
We report simultaneous measurements of shear viscosity (η) and dielectric constant (ε) of octyloxy cyanobiphenyl (8OCB) in the nematic (N) and smectic-A (SmA) phases as functions of temperature and electric
field. With increasing electric field η increases in the N phase whereas it decreases in the SmA phase and saturates beyond a particular field in both the phases.
The flow curves in the intermediate-field range show two Newtonian regimes in the N phase. The temperature-dependent behavior
of η and ε at zero or at small electric field suggests the occurrence of several structures that results from precessional motion of
the director along the neutral direction as reported in similar other system. We show that the precessional motions are gradually
suppressed with increasing electric field and the effective viscosity resembles with the Miesowicz viscosity η
1 at high enough electric field. In the intermediate field range the temperature-dependent η exhibits anomalous behavior across the N-SmA phase transition which is attributed to the large contribution of Leslie coefficient
α
1. 相似文献
114.
Enhancement of signal-to-noise ratio 总被引:2,自引:0,他引:2
Asish K. Dhara 《Journal of statistical physics》1997,87(1-2):251-271
It is shown that the ratio of signal-to-noise ratio at the output to that at the input can be made larger than unity when a nonlinear system is subjected to a weak periodic perturbation and a harmonic noise. This theoretical result is in conformity with the experimental observation published recently by R. Liet al. 相似文献
115.
Pandey A. Dhara S. Khan F. A. Kelkar A. Yadav R. Kumar Pradeep Sathe D. B. Bhatt R. B. Behere P. G. 《Journal of Radioanalytical and Nuclear Chemistry》2020,323(1):275-281
This paper presents studies on direct non-destructive determination of uranium in sintered deeply depleted (DD) uranium oxide (UO2) pellets by wavelength dispersive X-ray fluorescence (WDXRF) spectrometry. A special collet was designed and fabricated for holding the sintered DDUO2 pellets for direct analysis, thus avoiding the sample preparation steps. The samples were analyzed using a calibration plot obtained from WDXRF spectra of matrix matched calibration standards. The WDXRF determined uranium values were found to be in very close agreement with titrimetric values and has reproducibility better than 0.05% (RSD, 1 s, n = 10) for the sintered DDUO2 pellets having U: 86.81–88.04 wt%.
相似文献116.
Kaushik Sanyal Sangita Dhara S. Sanjay Kumar N. L. Misra P. K. Mollick P. T. Rao R. Venugopalan Rajesh V. Pai N. Kumar S. K. Mukerjee J. K. Chakravartty S. K. Aggarwal 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(3):1357-1361
A Total Reflection X-Ray Fluorescence (TXRF) methodology, employing burn-leach test, was developed to assess the quality of SiC layer in tristructural isotropic (TRISO) coated UO2 particles prepared in BARC. The coated particles were heated at 1,123 K for about 96 h to constant weight. The calcined particles, thus obtained, were then heated in suprapure concentrated nitric acid. The supernatant was analysed for trace elements by TXRF. No uranium was detected in this supernatant solution. The study demonstrates the good quality of SiC layer and applicability of TXRF for burn leach test of TRISO coated UO2 particles prepared. 相似文献
117.
In a recent paper Frolov, Hendy, and Larsen(1996) obtained a set of two nonlinear second-ordercoupled partial differential equations of 2D dilatongravity. They obtained a special solution assuming all the dependent variables were independent oftime. In the present work we reduce the above set ofequations to a simple form, from which we obtain a classof solutions that includes the solution of Frolov, Hendy, and Larsen as a special case. 相似文献
118.
Sangita Dhara N.L. MisraS.K. Aggarwal V. Venugopal 《Spectrochimica Acta Part B: Atomic Spectroscopy》2010
An energy dispersive X-ray fluorescence method for determination of cadmium (Cd) in uranium (U) matrix using continuum source of excitation was developed. Calibration and sample solutions of cadmium, with and without uranium were prepared by mixing different volumes of standard solutions of cadmium and uranyl nitrate, both prepared in suprapure nitric acid. The concentration of Cd in calibration solutions and samples was in the range of 6 to 90 µg/mL whereas the concentration of Cd with respect to U ranged from 90 to 700 µg/g of U. From the calibration solutions and samples containing uranium, the major matrix uranium was selectively extracted using 30% tri-n-butyl phosphate in dodecane. Fixed volumes (1.5 mL) of aqueous phases thus obtained were taken directly in specially designed in-house fabricated leak proof Perspex sample cells for the energy dispersive X-ray fluorescence measurements and calibration plots were made by plotting Cd Kα intensity against respective Cd concentration. For the calibration solutions not having uranium, the energy dispersive X-ray fluorescence spectra were measured without any extraction and Cd calibration plots were made accordingly. The results obtained showed a precision of 2% (1σ) and the results deviated from the expected values by < 4% on average. 相似文献
119.
Let R be a prime ring of char R ≠ 2, let d be a nonzero derivation of R, and let ρ be a nonzero right ideal of R such that [[d(x)x n , d(y)] m , [y, x] s ] t = 0 for all x, y ? ρ, where n ≥ 1, m ≥ 0, s ≥ 0, and t ≥ 1 are fixed integers. If [ρ, ρ]ρ ≠ 0 then d(ρ)ρ = 0. 相似文献
120.
S. Dhara A. K. Arora Santanu Bera Jay Ghatak 《Journal of Raman spectroscopy : JRS》2010,41(10):1102-1105
Raman spectroscopic studies have been performed for ZnS nanoclusters in this study. Cluster size dependent multiphonon properties are reported in detail. A flurry of zone boundary phonons is demonstrated in the scattering process. A strong deformation potential (DP) dominated Raman spectra are reported for cubic ZnS nanocluster of diameter with ∼2.2 nm in size below the quantum confinement. Transverse optic (TO) mode in the multiphonon process shows only even order overtones for 2.2 nm cluster, suggesting the dominance of a two‐phonon process and its integral multiples. The possibility of surface oxidation in the smallest cluster is ruled out as a plausible explanation for the observed even order TO modes which resemble the higher order modes of ZnO. A wave vector‐independence of electron–phonon interaction in quantum dots leads to strong dependence on DP‐related phenomenon. A large DP value for the second‐order process in ZnS than that with respect to the first‐order process is made responsible for the observed phenomenon. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献